Changing chainring on Bosch Performance Gen 5 Smart motor

[mintyjim]

Hi there,
I want to drop from 36t to 34t and when I took off the existing 36t ring it had a flange that’s missing from my 34t replacement.
Do I need a spacer or is it simply the wrong chainring. The 34t on my wife’s Mondraker is also missing a flange.
Plus, do I really need that stupid rubber o-ring that bunches up and splits when you torque the nut?
Finally, is it good practice/ necessary to replace the lock nut for each installation? Is it a stretch nut?
Many thanks!

Existing

Replacement

 

[mintyjim]

Bumpy bump…

I can’t believe no one has the knowledge and expertise to feedback on my questions!

Further drivetrain dilemma’s now include a SRAM chain skipping on an e thirteen chainring, at the bottom. FYI, I’m running 11s Linkguide

God I wish there was a decent gearbox/motor combo out there, I’m so bored of constant drivetrain maintenance.

Along comes someone to tell me that they’ve done 10,000 km on the same chain and derailleur and it’s never skipped a beat!

 

[Bogdan_CH]

Nobody replied I plan to change my chainring as well but wondering if there is a difference between Bosch Gen 4 and Gen 5 chairings

 

[SEBA]

i think the elevated chainring is 55mm chainline

sram do 2 models for example, 53 and 55

 

[SEBA]

Nobody replied I plan to change my chainring as well but wondering if there is a difference between Bosch Gen 4 and Gen 5 chairings

i think theres no différence

 

[Bogdan_CH]

Wollftooth confirmed me they fit. Indeed they fit as well. Just the chailine seems a bit different from stock so I would say

Stock 53,

New one from Woolf

55 mm

Hope it it won't affect the shifting.

 

[SEBA]

Wollftooth confirmed me they fit. Indeed they fit as well. Just the chailine seems a bit different from stock so I would say

Stock 53,

New one from Woolf

55 mm

Hope it it won't affect the shifting.

2mm is not a big difference, should work no problemo

 

[Ark]

theres different chainlines for boost and non boost or whatever. you bought the wrong one.
also Is the one you bought actually for bosch motors? should be labelled as direct mount or some such.
The chainrings are motor specific, normal chainrings don't fit on ebikes

Boost is a wider hub and axle standard on mountain bikes, increasing the hub flange spacing for enhanced wheel stiffness and tire clearance. Specifically, Boost widens the rear axle by 6mm (from 142mm to 148mm) and the front axle by 10mm (from 100mm to 110mm). This wider spacing allows for stronger, stiffer wheels, particularly beneficial for larger wheel sizes like 29ers. It also provides more clearance for wider tires and improved drivetrain compatibility.

 

[António13_PT]

If you search in Google for : "Bosch Gen 5 Chainring"

you get in the first results :

SRAM XX Eagle Transmission Chainring for Bosch Gen. 5 E-MTB | DU38 34

SRAM XX Eagle Transmission chainring for Bosch Gen 5 E-MTB | DU38 The engineers at SRAM have designed a chainring that counteracts the high forces and wear

r2-bike.com

You can se the chainline is 55 mm

With 53 mm, you will have more wear in the chain and in the smaller sprockets of the cassette, since the chain will have a greater lateral curvature

The biggest problem you have to look out for, is whether the chainring is too close to the frame.
Adjust the chainguide if you have one

 

[SEBA]

just add a washer behind the chainring if you are too close, 1mm for example, not too thick because not enough threads after

 

[RN611]

Nobody replied I plan to change my chainring as well but wondering if there is a difference between Bosch Gen 4 and Gen 5 chairings

I am in the same boat! And no info anywhere! I guess I will have to try and see if it works. I am running 12 SPD SRAM boost and just ordered a chainring with 55 mm offset from SRAM. I will see if it works with my chain line!
I will update once installed.

 

[Bogdan_CH]

I'm changing mine tomorrow so I'll update as well but for sure the 55 chainline fits spot on